1. Field
This document relates to an electrostatic capacitive type touch screen panel.
2. Related Art
In recent years, display devices, such as a liquid crystal display, an electroluminescent display, and a plasma display panel, having a quick response speed, low power consumption, and an excellent color reproduction rate, have been in the spotlight. These display devices have been used for various electronic products such as a television, a monitor for a computer, a laptop computer, a mobile phone, a display unit of a refrigerator, a personal digital assistant, and an automated teller machine. In general, these display devices interface with various input devices such as a keyboard, a mouse, and a digitizer. However, in order to use a separate input device, such as a keyboard or mouse, a user has to deal with the inconveniences of learning how to use it and taking up space, thus making it difficult to improve the degree of completion of the product. Therefore, the demand for input devices that are convenient and easy to use and reduce an erroneous operation is growing more and more. In response to this demand, a touch screen panel for enabling a user to input information by directly touching the screen with their hand or a pen was suggested.
Because the touch screen panel has a simple configuration, causes few erroneous operations, can perform an input action without a separate input device, and offers the convenience of allowing the user to quickly and easily manipulate content displayed on the screen, the touch screen panel is applied to various display devices.
Touch screen panels are classified into a resistive type, a capacitive type, an electromagnetic type and so on according to a detection method of a touched portion. The resistive type touch screen panel detects a touched portion by a voltage gradient according to resistance in a state that a DC voltage is applied to metal electrodes formed on an upper plate or a low plate. The capacitive type touch screen panel senses a touched position according to a difference in capacitance created in an upper or lower plate when the user touches an equipotential conductive film formed on the upper or lower plate. The electromagnetic type touch screen panel detects a touched portion by reading an LC value induced as an electromagnetic pen touches a conductive film.
Hereinafter, a related art electrostatic capacitive type touch screen panel will be described with reference to FIG. 1. FIG. 1 is a plan view of a related art electrostatic capacitive type touch screen panel.
Referring to FIG. 1, the related art electrostatic capacitive type touch screen panel comprises an electrode forming part A, a routing wire forming part B, and a pad forming part C.
The electrode forming part A comprises a plurality of first electrodes 21 formed on a substrate 10 and arranged in parallel in a first direction (e.g., the X-axis direction) and a plurality of second electrodes 22 arranged in a vertical direction (e.g., the Y-axis direction) to cross over the first electrodes 21. Although the first electrodes 21 and the second electrodes 22 cross over each other, they are kept electrically insulated by an insulation layer (not shown). Moreover, the neighboring first electrodes 21 are separated from each other, but connected to each other by bridges 25, thereby forming a first channel in a row direction. That is, the bridges 25 connect the neighboring first electrodes 21 to each other via contact holes 30a and 30b formed in the insulation layer 30 covered on top of the first and second electrodes 21 and 22, whereby a first channel having the first electrodes 21 connected together is formed in a row direction. Further, the second electrodes 22 are formed integral with each other, thereby forming a second channel in a column direction to cross over the first channel.
The routing wire forming part B comprises a plurality of first routing wires 42 formed outside the electrode forming part A and connected to the plurality of first electrodes 21 via contact holes 30c and 30d and a plurality of second routing wires 43 connected to the plurality of second electrodes 22 via contact holes 30e and 30f. The first routing wires 42 and the first electrodes 21 are connected to each other by first jumping bridges 45a formed on the insulation layer 30, and the second routing wires 43 and the second electrodes 22 are connected to each other by second jumping bridges 45b. 
The pad forming part C comprises a plurality of first pads 61 connected to the plurality of first electrodes 21 via the plurality of first routing wires 42 and a plurality of second pads 62 connected to the plurality of second electrodes 22 via the plurality of second routing wires 43.
As thus, the related art electrostatic capacitive type touch screen panel requires the first and second jumping bridges 45a and 45b to connect the first and second electrodes 21 and 22 of the electrode forming part A to the first and second routing wires 42 and 43 of the routing wire forming part B. The jumping bridges 45a and 45b and the first and second routing wires 42 and 43 are, however, made of metal in order to reduce electrical resistance. Therefore, when the touch screen panel is driven, the first and second jumping bridges 45a and 45b and the first and second routing wires 42 and 43 become visible at the interface between the electrode forming part A and the routing wire forming part B (hereinafter, referred to as a visibility phenomenon).
Moreover, as the insulation layer 30 is formed between the first and second electrodes 21 and 22 of the electrode forming part A and the first and second routing wires 42 and 43 of the routing wire forming part B, the contact holes 30c, 30d; 30e, 30f need to be formed in the insulation layer 30 in order to connect the first and second electrodes 21 and 22 to the first and second routing wires 42 and 43. In general, in order to improve touch accuracy on the touch screen panel, the first and second electrodes 21 and 22 are made so small, and the first and second routing wires 42 and 43 have a very small line width because they are formed to be compact in a narrow space. Accordingly, the diameter of the contact holes 30c, 30d; 30e, 30f formed in the insulation layer 30 to connect the first and second electrodes 21 and 22 and the first and second routing wires 42 and 43 is very small. As the resistance of a certain object is in inverse proportion to the cross-sectional area thereof, the resistance of the first and second jumping bridges 45a and 45b filled in the contact holes 30c, 30d; 30e, 30f having a small diameter increases. Accordingly, if static electricity enters from the outside during a panel fabricating process, module fabricating process, or product transportation, a temporarily high current abruptly flows through the first and second jumping bridges 45a and 45b, and this may damage the contact holes 30c, 30d; 30e, 30f. 